1. Field of the Invention
The present invention relates to a stage base, a substrate processing apparatus, and a maintenance method for a stage which are suitable for making a semiconductor device, for example.
2. Related Background Art
As a substrate processing apparatus, a lithography system utilizing an electron beam is equipped with a vacuum chamber. The upper wall of the vacuum chamber is provided with an irradiation unit for emitting the electron beam, whereas a wafer stage for positioning and holding a semiconductor wafer is disposed within the vacuum chamber.
For example, the electron beam lithography system disclosed in Japanese Patent Application Laid-Open No. HEI 4-171715 comprises a wafer stage including X and Y tables for positioning and holding a semiconductor wafer, and further comprises a stage base for mounting the wafer stage.
In this lithography system, the Y table is mounted on the X table so as to be movable along the Y axis. The X table is mounted on the stage base so as to be movable along the X axis. By way of wheels attached to side faces extending along the Y axis, the stage base is made movable on a reference surface of the main chamber.
In such a lithography system, the stage base is positioned by being connected to a side wall part of the vacuum chamber. At the time of maintenance for the wafer stage, the stage base and the side wall part are drawn together in the Y direction, so that the maintenance for the wafer stage can be performed on the outside of the vacuum chamber.